As a nurse manager, it is your responsibility to make sure that the team is functioning well. This means being a leader. You have to take steps immediately when someone is not being cooperative. Never avoid the issue.
Be sure to talk to the uncooperative nurse alone at the first sign of the behavior. You want to learn the root of it. Make sure you know the whole story, including what might have instigated the incident. Do not take sides against the one you think is at fault right away. People are going to be more compliant when they feel they are heard.
Give a warning, and document the behavior. Make sure the nurse knows that it is unacceptable, and try to give the person tool s to better handle the situation in the future. Keep an eye on it. Also, be sure to talk to the other person involved alone too, to make sure you have the full story before you act further.
The first thing you need to do as a nurse manager is know your team. Try to get to know each one individually, and their personalities. If possible, try to have nurses working together that are compatible and get along. Avoid mixing people with personality conflicts when you can. If you know your nurses first, then you can more easily have them work together.
Next, help your nurses get to know each other. Have team activities that are more fun than work, such as going to lunch or going bowling. It may sound cheesy, but when people get to know each other out of the workplace setting they see another side of each other, and may be more reasonable.